What it does
Any amount of damage dealt by a creature with deathtouch is "lethal." So if a deathtouch creature deals even 1 damage to another creature, that creature is destroyed (assuming it isn't indestructible or doesn't have its damage prevented).
The biggest misconception: deathtouch doesn't kill instantly on contact—it only matters when damage is dealt. It also doesn't bypass indestructible, and damage prevention/fog effects stop it entirely. In combat, deathtouch interacts with trample: an attacker only needs to assign 1 damage to each blocker before assigning the rest to the player, making big deathtouch tramplers brutal.
In Commander, deathtouch is excellent defensively—a small deathtoucher discourages attacks from much larger creatures and trades up. It pairs nastily with ping effects, fight spells, and "deals damage to multiple creatures" abilities (one source killing several blockers at once).













